pc hdmi connection issue

hi,
I have got a annoying issue with the connection of my notebook and my TV.

My Notebook is always connected to the TV by HDMI.

Problem: Always if I turn on the TV while the notebook is running, the TV is automatically used as single windows desktop and my notebook display turns off.
Does anybody know how to configure windows or TV to stop this?

a) I tried the update function while tv was connected to the internet. it told me, that the firmware is current version

b) in the control panel i set the option "Show Desktop only on Computer". but if I turn on the TV (while it's connected by hdmi to the computer) the option is changing automatically to "Show Desktop only on projector"
Of curse I can rechange the option everytime it happens, but thats annoying. I'm wondering whether there is somewhere an option to turn off automatical changing

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